loading games from usb flashdrive on wii

i wanted to know if backups work perfectly on the wii if they are loaded off a usb flashdrive,i have heard rumors of the games being played with completely no lags,is it true?and does wifi playing game such as ssbb also play perfect with the wifi compatibility also?
and is there a certain usb flash drive needed?a certain size?etc.....
and what program is needed to run them off it?
thanks.